IMO,
Webmaster forums = Educational w/ some spam
MySpace = Maximum Spam, Crappy Ads.
Digg = OK, but does popular equal good?
Facebook = Possibly good, have you joined, yet?
Twitter = Seems really spammy to me, but some people claim it's very targeted and useful.
What do you think?
Is Social Networking Fun and Useful, or Just A Bunch Of Spam?